Climate change, driven by rising greenhouse gas levels, is intensely relevant
to the 340,000 or so people living in the Maldives
IMHO, the silver bullet for atmospheric carbon reduction is clearly solar power.
Though “always available” solar power schemes, such as photovoltaic panels in space beaming power to the ground, exist, they’re unfeasible. Near-term, solar power systems must be ground based. The glaringly obvious technical hurdle for producing a useful, constant supply of electic power with ground-based solar power systems is energy storage – because there is no sunlight, and thus no solar power for a given ground station, at night, and reduced power early and late in the day, and when there are many clouds.
There are 2 main feasible families of solutions to this problem: solar thermal systems such as solar updraft towers
, which store energy as heat, and can produce near even power levels through the 24 hour cycle, and ones that store energy excess daytime electric power, such as the Solar Grand Plan
, which stores energy as compressed air in large underground chambers which can be draw upon (in a complicated way) when the sun and solar-generated electricity are down.
These are big, expensive, economically challenging systems, hard to scale down in the manner of a microgrid
. (The microgrid approach promises to reduce total cost, allowing new systems to be gradually implemented)
Enter electric cars.
Our cars are powerful, many times more than required by our households. A typical house draws perhaps 4500 W peak, while even a small car produces at least 40000 W (54 HP). Electric cars can be charged during the day from solar power source, then discharged to power households during the night.
Though other schemes, such as flywheels and regenerative fuel cells, have tantalized, the best looking at present are electrochemical batteries. Looking at total energy cost, the one-time cost of a battery is less important than its lifespan – a US$100,000, 2 GJ battery with a lifespan of 50 years is nearly as economical as a $10,000, 10 year one.
Alas, there’s no such battery yet. Though chemistries like the lithium–titanate battery
are promising (as many as 20,000 full charge-discharge cycles – 20 years of daily cycles – with less than 10% capacity loss), such batteries are small (less than 11 MJ ) and expensive. One of the major makers, Altairnano, had a financial meltdown in 2014, and was being sued by it shareholders.
A breakthrough in battery technology along these lines, in cost and chemistry, could be revolutionary – a siver bullet.